1. Field of the Invention
The present invention relates to flexible containers, and more particularly, to a transparent type of flexible container for use in containing liquids directed for human consumption.
2. Description of the Prior Art
In the bulk liquid container field, particularly with regard to servicing restaurants and the like, a five-gallon size container has been found to be the best size of container. In the past, milk was delivered to restaurants and public dining facilities in metal containers. Then came the advent of the corrugated carton having a polyethylene liner fixed to the inside of the carton, and a heavier density polyethylene spout attached to both the liner and the carton. These containers were ideal for stacking and for handling, and the costs of shipping were reduced since the containers were disposible. However, with the ever-increasing cost of fiberboard material, such as corrugated boxes, a new flexible disposible pouch has been developed to replace the corrugated box with the liner container.
The newer container is in the form of a five-gallon pouch made up of a double wall of polyethylene material with a heavier density polyethylene spout piercing a wall of the pouch and adhered thereto in a sealed manner.
In the era of the carton box with the polyethylene liner, it was reasonably easy to identify the product, the date the product was filled in the flexible container, and the trade mark label of the dairy supplying the bulk milk, since this need merely be adhered to the outer box or printed thereon. However, there are problems in labeling the present flexible pouch made up of transparent polyethylene sheet material. It is well known to print on such polyethylene sheet material by first treating the sheet material with a corona discharge. However, sheet material which has been treated by corona discharge tends to be less susceptible to heat sealing, and a strong heat seal bond is essential when one is dealing with five-gallon liquid pouches.
Furthermore, since the film being used to form the pouches is supplied in rolls, the rolls must be unwound in order to print adjacent layers of double wound film. The film is thus exposed to the atmosphere, and furthermore, the under-wound film, which is destined to form an inner surface and therefore be in contact with the milk, is in contact with the ink on the printed film, thereby possibly retaining odors from the ink and transferring these to the milk. It is preferable that the film to be used for forming the liquid pouches have as little exposure to the atmosphere as possible to reduce contamination. Further, it is evidently undersirable to have ink odors transferred to the contents of the pouches.
An obvious solution would be to provide sticker type labels which can be adhered to the outside surface of the pouch. However, these stickers can be accidentally or deliberately removed during handling, thereby increasing the risk of aged or otherwise contaminated milk or other food products being passed on to the public.